Flexible electrical transmission member

ABSTRACT

A flexible bellowslike electrical transmission member having rigid end sections is vibration damped by a jacket of resilient elastic material deposited on the bellows. The elastic jacket completely surrounds the ends of the bellows and has narrow strips extending along the middle of the bellows. The flexible bellows are joined to each rigid end section by a rigid face-toface connection between a fin of the bellows and a surface of the rigid end section.

United States Patent lnventors Donald L. Herling Mundelein; Frank A.Larson, Lombard; George F. Kovar, Berwyn, all of, I11.

Appl. No. 832,238

Filed June 11, 1969 Patented July 20, I971 FLEXIBLE ELECTRICALTRANSMISSION MEMBER 6 Claims, 4 Drawing Figs.

[15. Cl 1138/121, 333/95 lnt.Cl ..F161 11/00, 1101;) 3/12 Field ofSearch 138/109, 143,139,121,120,118,109;333/95,95 A

References Cited UNITED STATES PATENTS 1,475,289 11/1923 Diescher138/118 X 1,505,121 8/1924 Allport. 138/121 X 2,600,169 6/1952 Lambm.138/121 X 2,657,364 10/1953 Carr 138/121 X 2,675,832 4/1954 Hamilton138/121 X 2,696,834 12/1954 Carr 138/121 X 2,758,612 8/1956 Zaleski138/121 X 3,307,589 3/1967 Sheffield 138/109 3,479,621 11/1969 Martin138/143 X Primary Examinerl-1enry K. Artis Attorneyl-lofgren, Wegner,A11en.,Ste11man & McCord ABSTRACT: A flexible bellowslike electricaltransmission member having rigid end sections is vibration damped by ajacket of resilient elastic material deposited on the bellows. Theelastic jacket completely surrounds the ends of the bellows and hasnarrow strips extending along the middle of the bellows. The flexiblebellows are joined to each rigid end section by a rigid face-to-faceconnection between a tin of the bellows and a surface of the rigid endsection.

PATENIED JUL20 I971 @NQ mw FLEXIBLE ELECTRICAL TRANSMISSION MEMBER Thisinvention relates to a flexible electrical transmission member.

To interconnect rigid electrical transmission members which are notaxially aligned, a flexible electrical transmission member is used whichmaintains the electrical transmission characteristics of the rigidmembers and allows misalignment and relative motion or vibration betweenthe rigid members. Such flexible member is usually of bellowslikeconstruction, formed by a plurality of sections having integral fins.The flexible member may for example, be in the form of a wave guide orcoaxial transmission line.

Such flexible electrical transmission members have heretofore beensubject to undesirable vibration and flexing due to inadequate dampingcaused by the metallic construction of the bellows. Vibrations occurringat the joint between the flexible member and a rigid member causeundesirable fatigue and eventual failure. in addition, the center partof flexible bellows tends to bow when the section is under pressure.

in accordance with the present invention, a resilient elastic jacket ismolded to the flexible electrical transmission member to eliminate theseproblems. The jacket encircles the bellows at the joint where thebellows joins a rigid end member, damping vibrations at the joint andreducing metal fatigue. The jacket is of reduced dimensions at thecenter part of the bellows to resist bowing of the bellows and also todamp vibrations while maintaining the flexing properties of the bellows.Fatigue at the joint between the bellows and the rigid member is furtherreduced by a coupling in which an end fin of the bel lows is maintainedin rigid face-to-face contact with a surface of the rigid memberthroughout substantially the whole length of the fin.

One feature of this invention is the provision of a flexible electricaltransmission member having a resilient elastic jacket molded thereon.

Another feature of this invention is the provision of flexibleelectrical transmission member having a rigid face-to-face coupling forthe joint between the flexible member and a rigid member connectedthereto.

Further features and advantages will be pointed out in the followingspecification, and in the drawings, in which:

FIG. l is a front plan view of the invention as embodied in a flexiblewaveguide;

FIG. 2 is a cross-sectional view taken along lines 2-2 of FIG;

F lG. 3 is a front plan view on a reduced scale and showing the flexiblemember in a flexed position; and

FIG. 4 is a fragmentary sectional view taken along lines 4-4 of HO. 1.

While an illustrative embodiment of the invention is shown in thedrawings and will be described in detail herein, the invention issusceptible of embodiment in many different forms and it should beunderstood that the present disclosure is to be considered as anexempliflcation of the principles of the invention and is not intendedto limit the invention to the embodiment illustrated. The scope of theinvention will be pointed out in the appended claims.

Turning to FIG. 1, the invention is illustrated as embodied in aflexible wave guide consisting of a flexible bellowslike sectionllljoined to rigid end sections 12. End'sections 12 are illustrated asrigid flanges for connection to other rigid wave guide members, but mayalternatively be a contiguous part of another rigid waveguide member.While the drawings illustratively show a rectangular waveguide, it willbe understood that the present invention is applicable to other flexibleelectrical transmission members, such as a coaxial connector in whichthe outer conductor and the coaxial inner conductor are each ofcylindrical bellows configuration, as well as to other shapes of waveguides.

Bellows section ll consists ofa plurality of riblike body sections Ml,see also FIG. 4, in axial alignment and joined together by a series ofconvolutions or integral fins 115 of hollow, riblike or channelstructure. Each fin has a pair of side walls 16 contiguously joined toeach adjacent section 14. The ribs 15 circumferentially surround thebody sections M and have open channel portions facing radially inward.When the bellows section 111 is not under tension, the sidewalls l6 liein plane substantially normal to the longitudinal axis of bellow section111.

The body and rib or fin portions of the bellows are manufactured byforming a mandrel which is shaped substantially like the bellows to beproduced. The mandrel is plated with a desired thickness of metal, suchas nickel, after which the mandrel is dissolved leaving only the platedmaterial in the bellows shape. Thereafter, the bellows are again platedwith a desired thickness of electrically conductive material such asgold or silver to give the desired electrical characteristics to thebellows section.

To damp vibrations in transmission member 10, a resilient elastic jacket20 is molded to bellows section 11!. Jacket 20 is deposited over theradially outer side of the bellows, and fills the outer facing channelsbetween the side walls 16, see FIG. 4. The jacket extends slightly abovethe top of fins 15, so as to form a substantially flat outer surfaceparallel to the elongated axis of the waveguide. Jacket 20 may be formedof any resilient material having the desired damping properties, such asa silicone rubber which vulcanizes at. the ambient temperature at whichthe wave guide is to be utilized.

The end joints where the bellows section 11 joins each of the rigidflanges 12 has improved life due to the damping action of jacket 20 anddue to an improved faee-to-face coupling between the flexible and rigidsections. Referring to FIG. 4, illustrating the right most coupling,which is identical to the leftmost coupling (not illustrated), the lastsection 1141 of the flexible member has an integral single sidewall 15'which extends radially outward therefrom. Wall ]l5 terminates at the topof its radially outer extent. Substantially the whole radial extent ofwall 15 abuts a radially extendling wall 23' of a lip 23 of rigid endsection 12. The radially innermost longitudinal surfaces of sections 14form a substantially continuous plane with respect to the frequency ofelectrical energy being transmitted through the wave guide. This planeis aligned with the longitudinal inner surface of rigid flange 12.Typical couplings between a flexible and rigid wave guide allow movementbetween the last radially extending fin and a radially extending rigidwall.

In accordance with the present invention, substantially all of wall ll5is rigidly maintained against wall 23 of lip 23, for both the flexed andunflexed positions of the waveguide. The means for maintaining wall 15rigidly against wall 23 may take several forms. The form illustratedconsists of a bracket 25 of L-shaped cross section. Bracket 25 has aradially extending wall 27 which abuts wall 15', and a contiguous wall28 which is transverse to wall 27 and abuts a circumferential,longitudinal extending surface of lip 23. A screw 30 extends through anaperture in wall 28 and is threaded into an internally threaded aperturein lip 23, to thereby clamp wall 115' against lip 25. Alternatively,wall 115 may be maintained against wall 23 by brazing.

To further reduce fatigue at the joint, resilient jacket 20 at each endsection 30 is molded to continuously surround a number of bellowsections 14 adjacent each end wall. As seen in FIG. 4, the molded endjacket section 30 extends up to and fills the last channel in thebellow, thus bridging the bellows and a portion of the rigid waveguide,as bracket 25. At a middle or center section of the bellows, the jacket20 necks down to strips 31 of resilient material. As seen in FIG. 2, apair of strips 31 are located on the two opposite sides of the waveguide which are of greater dimensions. Strips 31 extend into sections ofcontinuously increasing circumferential extent and finally join the endsections 30 which continuously surround the bellows. The center strips311 serve to damp the bellows and also to resist bowing in the bellowswhen the bellows are under pressure.

We claim:

1. A vibration damped flexible electrical transmission waveguide,comprising:

a flexible conductor of bellowslike configuration formed by a pluralityof sections joined by integral fins;

a layer of elastic material deposited on said conductor and covering aplurality of sections thereof to damp vibrations therein;

a pair of rigid electrical transmission conductors each joined to anopposite end of said flexible conductor, said layer of elastic materialextending on said flexible conductor continuously from one of said rigidtransmission conductors to the other of said rigid transmissionconductors, wherein said rigid conductors each have a radially extendingend surface, the terminating portions of said flexible conductor eachinclude a radially extending fin terminating at its outer radial extent,and means maintaining said fins rigidly against said end surfaces tojoin said flexible conductor to said pair of rigid conductors.

2. A vibration damped flexible electrical transmission member,comprising:

a flexible conductor of bellowslike configuration formed by a pluralityof sections joined by integral fins;

a layer of elastic material deposited on said conductor and covering aplurality of sections thereof to damp vibra tions, wherein said elasticlayer completely encircles a plurality of sections adjacent each end ofsaid flexible conductor, and said elastic layer further includes elasticmaterial on the middle portion of said flexible conductor in at leastone strip of material extending over less than the circumference of themiddle portion of said flexible conductor.

3. The transmission member of claim 2 wherein said flexible conductorhas a rectangular cross section defined by two walls of greater extentthan two walls transverse thereto, and the elastic material deposited onthe middle portion of said flexible conductor extends longitudinally instrips along said two walls ofgreater extent.

4. In a flexible electrical transmission waveguide of bellowslikeconfiguration formed by a plurality of sections joined by integral fins,said fins each having a pair of side walls con tiguously joined to eachadjacent section and a rigid electrical transmission member joined tosaid flexible member, the improvement comprising:

an end portion for said flexible member consisting of a single side wallextending radially and terminating at the top of its radial extent,

a radially extending end surface for said rigid member adjacent saidsingle sidewall; and

means maintaining said single sidewall rigidly against said end surfacethroughout substantially the whole radial extent of said sidewall toprevent movement between the last radially extending fin and theradially extending rigid end surface so that a substantially continuousplane with respect to the frequency of electrical energy beingtransmitted through the waveguide is formed.

5. The transmission waveguide of claim 4 wherein said maintaining meansincludes a bracket having a radially extending wall located adjacentsaid single sidewall and a wall transverse to said radially extendingwall and located adjacent an axially extending surface of said rigidmember, and means fixedly attaching said transverse wall to said axiallyextending wall in order to clamp said flexible member to said rigidmember.

6. The transmission waveguide of claim 4 wherein said flexible memberincludes a layer of elastic material deposited on said flexible memberand covering a plurality of sections to damp vibrations in said flexiblemember.

I I I UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3593 751 Dated July 20 1971 Inventor) Donald L. Herling et a1 It iscertified that error appears in the aboveidentified patent and that saidLetters Patent are hereby corrected as shown below:

On the cover sheet insert [73] Assignee The Hallicrafters Co.

Signed and sealed this 15th day of February 1972.

(SEAL) Attest:

EDWARD M. FLETCHER ,JR

ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORMF'O-105U (10-69) USCOMM-DC 60375P6D R U S GOVERNMENT PRINTING OFFICEJIQS O365-334

1. A vibration damped flexible electrical transmission waveguide,comprising: a flexible conductor of bellowslike configuration formed bya plurality of sections joined by integral fins; a layer of elasticmaterial deposited on said conductor and covering a plurality ofsections thereof to damp vibrations therein; a pair of rigid electricaltransmission conductors each joined to an opposite end of said flexibleconductor, said layer of elastic material extending on said flexibleconductor continuously from one of said rigid transmission conductors tothe other of said rigid transmission conductors, wherein said rigidconductors each have a radially extending end surface, the terminatingportions of said flexible conductor each include a radially extendingfin terminating at its outer radial extent, and means maintaining saidfins rigidly against said end surfaces to join said flexible conductorto said pair of rigid conductors.
 2. A vibration damped flexibleelectrical transmission member, comprising: a flexible conductor ofbellowslike configuration formed by a plurality of sections joined byintegral fins; a layer of elastic material deposited on said conductorand covering a plurality of sections thereof to damp vibrations, whereinsaid elastic layer completely encircles a plurality of sections adjacenteach end of said flexible conductor, and said elastic layer furtherincludes elastic material on the middle portion of said flexibleconductor in at least one strip of material extending over less than thecircumference of the middle portion of said flexible conductor.
 3. Thetransmission member of claim 2 wherein said flexible conductor has arectangular cross section defined by two walls of greater extent thantwo walls transverse thereto, and the elastic material deposited on themiddle portion of said flexible conductor extends longitudinally instrips along said two walls of greater extent.
 4. In a flexibleelectrical transmission waveguide of bellowslike configuration formed bya plurality of sections joined by integral fins, said fins each having apair of side walls contiguously joined to each adjacent section and arigid electrical transmission member joined to said flexible member, theimprovement comprising: an end portion for said flexible memberconsisting of a single side wall extending radially and terminating atthe top of its radial extent, a radially extending end surface for saidrigid member adjacent said single sidewall; and means maintaining saidsingle sidewall rigidly against said end surface throughoutsubstantially the whole radial extent of said sidewall to preventmovement between the last radially extending fin and the radiallyextending rigid end surface so that a substantially continuous planewith respect to the frequency of electrical energy being transmittedthrough the waveguide is formed.
 5. The transmission waveguide of claim4 wherein said maintaining means includes a bracket having a radiallyextending wall located adjacent said single sidewall and a walltransverse to said radially extending wall and located adjacent anaxially extending surface of said rigid member, and means fixedlyattaching said transverse wall to said axially extending wall in orderto clamp said flexible member to said rigid member.
 6. The transmissionwaveguide of claim 4 wherein said flexible member includes a layer ofelastic material deposited on said flexible member and covering aplurality of sections to damp vibrations in said flexible member.